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Tektronix TDS744 CRT to LCD color converter FPGA module DIY

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Tantratron:

--- Quote from: TerrySt on December 10, 2023, 05:58:40 pm ---I used a Spartan 7 dev board from Trenz.  It was the smallest dev board I could find for a reasonable cost.  Others would work (with a new pcb layout of course).  The Spartan 7 is much larger than needed.  The design I ended up using only uses 49 FFs and 81 LUTs.  Just be sure what you choose supports a PLL or MMC module that can provide the 175MHz clock for the lvds interface to the lcd panel.  It needs to be phase locked to the 25MHz clock from the o'scope.

--- End quote ---

The owner of Simmcon labs has used a Spartan 3 (model XC3S50A), do you know if this is enough to implement 49 FFs (Flip-Flop) and 81 LUTs (Look Up Table) or he was super experimented to optimize its code with much lesser CLBs (Configurable Logic Blocks) ?


--- Quote from: TerrySt on December 10, 2023, 11:08:29 pm ---None of the dev boards that I could find (at least the reasonably priced ones) allow you to set the voltages on the FPGA to the voltage required by the LVDS interface.  They all seem to be set to 3.3V, and for LVDS you must set the domain voltage to 2.5V

--- End quote ---

Interesting which explains now why Simmconn labs uses a local 1.2 Vdc regulator because when we see the G065VN01 V2 datasheet (page 11/24), it mesntions for LVDS the differential input common voltage VCM to be between 1.1V and 1.45V (typical 1.2 V) for best threshold detection.

Albert

TerrySt:

--- Quote from: Tantratron on December 11, 2023, 02:45:54 pm ---
--- Quote from: TerrySt on December 10, 2023, 05:58:40 pm ---I used a Spartan 7 dev board from Trenz.  It was the smallest dev board I could find for a reasonable cost.  Others would work (with a new pcb layout of course).  The Spartan 7 is much larger than needed.  The design I ended up using only uses 49 FFs and 81 LUTs.  Just be sure what you choose supports a PLL or MMC module that can provide the 175MHz clock for the lvds interface to the lcd panel.  It needs to be phase locked to the 25MHz clock from the o'scope.

--- End quote ---

The owner of Simmcon labs has used a Spartan 3 (model XC3S50A), do you know if this is enough to implement 49 FFs (Flip-Flop) and 81 LUTs (Look Up Table) or he was super experimented to optimize its code with much lesser CLBs (Configurable Logic Blocks) ?


--- Quote from: TerrySt on December 10, 2023, 11:08:29 pm ---None of the dev boards that I could find (at least the reasonably priced ones) allow you to set the voltages on the FPGA to the voltage required by the LVDS interface.  They all seem to be set to 3.3V, and for LVDS you must set the domain voltage to 2.5V

--- End quote ---

Interesting which explains now why Simmconn labs uses a local 1.2 Vdc regulator because when we see the G065VN01 V2 datasheet (page 11/24), it mesntions for LVDS the differential input common voltage VCM to be between 1.1V and 1.45V (typical 1.2 V) for best threshold detection.

Albert

--- End quote ---

I don't know anything about Spartan 3 but I bet even the smallest Spartan 3 has enough resources for this job.  You just need to make sure the version you choose has enough I/O.  Watch out for the way the I/O banks are defined.  You can't mix voltages in a bank.  So if you decide a bank is 3.3V for the I/O, then all of that bank is 3.3V.  I don't know if the Spartan 3 supports lvds in all of the devices or on all banks or what other restrictions there might be. 
The 1.2V is probably the core voltage.  It looks like the lvds requires 2.5 or 3.3V on the Spartan 3.
I would use the Spartan 3 except it looks like the only tools available are the ISE that only works on Win7 or Linux.  I'm not sure I want to mess with setting up a VM to run either Win7 or Linux.  What tool are you using?

Terry

Tantratron:

--- Quote from: TerrySt on December 11, 2023, 02:58:33 pm ---I would use the Spartan 3 except it looks like the only tools available are the ISE that only works on Win7 or Linux.  I'm not sure I want to mess with setting up a VM to run either Win7 or Linux.  What tool are you using?

--- End quote ---
I'm using MacOS being quite faithfull to Apple since 1986

TerrySt:

--- Quote from: Tantratron on December 11, 2023, 03:04:34 pm ---
--- Quote from: TerrySt on December 11, 2023, 02:58:33 pm ---I would use the Spartan 3 except it looks like the only tools available are the ISE that only works on Win7 or Linux.  I'm not sure I want to mess with setting up a VM to run either Win7 or Linux.  What tool are you using?

--- End quote ---
I'm using MacOS being quite faithfull to Apple since 1986

--- End quote ---

Is ISE supported on MacOS?

ltarjanyi75:
Hi,

Spartan 3 (model XC3S50A) should be fine, since SimmconnLabs use it in their design with LVDS also. They have an onboard 1.2V converter and 3.3V as input. 1.2V is used as internal supply voltage in Spartan 3.

I tested the G065VN01 V2 display with a Spartan 6 devboard bought from Aliexpress (Xilinx spartan6 XC6SLX16). It's VCCO and VCCAUX pins are connected to 3.3V and VCCINT (internal supply voltage) to 1.2V, no sign of any 2.5V either... I measured the voltage levels on LVDS output clock signal and it changes approx between 1.1V and 1.45V. What is strange that it is the same even if I set the LVDS output pins IOSTANDARD to LVDS_33 or LVDS_25... (Or I do something wrong...)

ISE can be installed and run on Windows 10 (there are other topics on the net), the issue for me is the IMPACT tool to download the compiled code to the FPGA. It does not work with my Xilinx platform cable (chinese clone) only trough Virtual Machine setup. At least I can develop in Windows 10 and to use the files from same project folder under VM to download the compiled code to FPGA.

Bye,
Laszlo

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